Rare Moon rock found in Antarctica

Scientists broke open meteorite MIL 05035 in the Antarctic Meteorite Processing Laboratory at NASA's Johnson Space Center to study its composition. The lunar meteorite's interior is pinkish-tan with an unusual granular texture. Each side of the cube shown is slightly less than half an inch (1 centimeter) in length.

Antarctic Search for Meteorites Program, Case Western Reserve University

September 18, 2006A team of geologists from Case Western Reserve University in Cleveland spent 6 weeks on an ice field in Antarctica in 2005 searching for meteorites. Their efforts were rewarded December 11, 2005, when they found a rare lunar meteorite.

The search team, part of the U.S. Antarctic Search for Meteorites program discovered the 5-ounce (142 grams), golf-ball-size meteorite on the Miller Range of the Transantarctic Mountains, located about 460 miles (750 kilometers) from the South Pole. Officially known as MIL 05035, the Moon rock is unlike the other 237 meteorites collected during the 2005-2006 Southern Hemisphere summer.

This microscopic view of a thin slice - less than 1/1,000th of an inch (30 micrometers) thick - of lunar meteorite MIL 05035 reveals the mineral pyroxene (bright mosaicized colors) and maskelynite (dark gray areas), which formed when an intense shock transformed feldspar into glass. MIL 05035's coarse grain size and inclusion of maskelynite are unusual among other lunar specimens.

Antarctic Search for Meteorites Program, Case Western Reserve University

Scientists at NASA's Johnson Space Center and the Smithsonian Institution's National Museum of Natural History confirmed the unusual specimen is a coarse-grained type of gabbro similar to basaltic lava typically found in the lunar maria. What separates MIL 05035 from typical lunar meteorites is its very large crystals and the presence of maskelynite, a type of glass that forms during an intense shock like an impact event. The meteorite's large crystals suggest this Moon rock slowly cooled deep inside the lunar crust.

The only other meteorite known to be similar in composition to MIL 05035 is Asuka 881757, which is among the oldest known lunar basalt specimens. Like MIL 05035, Asuka 881757 was also found in the Antarctic. Scientists think MIL 05035 is also very old because of its highly shocked nature.

Scientists worldwide may request samples of MIL 05035 to conduct their own research. Those interested can contact the NASA's Astromaterials Curation web site for more information.